Accuracy of different rapid urease tests in comparison with histopathology in patients with morphological signs of gastritis in endoscopy
09 May 2017 (online)
Helicobacter pylori (HP) is a gram negative, microaerophilic bacterium that was first discovered in 1982. It is one of the most important risks for gastroduodenal ulcer disease and distal gastric cancer. In addition, HP is an acknowledged oncogene for gastric MALT lymphoma, eradication of HP can cure the majority of HP related diseases and offers the unique chance to prevent gastric cancer. Corresponding to several guidelines different invasive and non invasive tests are possible to detect a HP infection. In detail invasive methods are HP culture, histological staining, rapid urease tests (RUTs) and PCR methods. Non invasive methods are urea breath test, HP stool antigen and serum IgG test. In our study we wanted to compare different RUTs with histology findings to determine sensibility and specificity of the different tests.
In our study we tested all five in Germany commercial available RUTs in comparison to histological staining in 150 real life patients with strong morphological signs of gastritis or gastroduodenal ulcers even if proton pump inhibitors (PPIs) or antibiotics were used. RUTs were checked after 30 min, 2h and 24hours. If the results of the RUTs and the histological staining were different, a PCR test to detect HP DNA was added. In 15 patients (10%) all five RUTs as well as histological examination were positive. In one patient 3 of 5 RUTs, the histological staining and the PCR test were positive. In one further patient 4 of 5 RUTs, the histological staining and the PCR test were positive. In three patients (2%) the results of histology and the RUTs were different. Although all five RUTs were positive in one patient, the histological staining was negative. Interestingly the PCR test showed a positive result for HP DNA in this patient. In summary 20 patients (13%) had an infection with HP in our study cohort. In two patients the RUTs did not detect an infection with HP, whereas the histological staining showed a false positive result, since the added PCR test showed a negative result. In 128 patients (85%) all five RUTs as well the histological staining were negative. There was no significant difference in sensitivity and specificity between the different RUTs. In conclusion, rapid urease test is a cheap and high potential test for the diagnosis of a HP infection with comparable sensitivity and specificity to histological staining. In PPIs or antibiotic pretreated patients rapid urease test may be even more sensitive compared to histology.